Before posting this, I looked at a similar thread, but could not find what I was looking for.

I am using Ubuntu at present. Learnt about kubuntu & xubuntu recently. Visited its websites to find out details.
Learnt that these are based on ubuntu.
KUbuntu uses KDE graphical environment.
XUbuntu uses XFCE graphical environment.

My need:

Programming for database oriented business apps using MySQL & Python. Use online stock-trading terminal based on Java.

Should I go for Ubuntu or XUbuntu or Kubuntu?
(I read that Xubuntu is faster than Kubuntu).

I am going to format my laptop. Before that, I want to download a latest copy of a good open source OS.

Can anyone please share on the following points:

Whether the default Xubuntu / Kubuntu installation is packed with open source software packages such as MySQL, Python, etc. or I need to download those separately?

Compared to Ubuntu, whether Xubuntu / Kubuntu have the 'software centre' which can take care of new / old installation of packages.

No setting-up of wireless internet was required in my existing Ubuntu. It was automatically detected & taken care of by the OS. What about Xubuntu / KUbuntu?

Performance point of view, how do they compare? e.g. My Ubuntu OS starts within 10 sec & shuts down in 3 secs

You should ask this on ubuntuforums.org Besides that: this site works with a 1 question, 1 best answer system. For this to work on AU it would be best to split this up into several questions. But... ubuntuforums.org is a far better platform to ask this type of questions. My opinion: what you ask does not matter and is the same for all flavours of Ubuntu. These 3 just use a different desktop manager. All the software that's not part of that is the same (mysql, python etc etc).
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RinzwindDec 23 '11 at 9:18

4 Answers
4

Okay I will add another spin there and answer your question in one line:

There is Lubuntu as well.

All of them are ubuntu. They are not different distros, they are different desktop environments.

Kubuntu is ubuntu with kde. Can be installed in ubuntu with meta-package kubuntu-desktop

Xubuntu is ubuntu with xfce. Can be installed in ubuntu with meta-package xubuntu-desktop

Lubuntu is ubuntu with lxde. Can be installed in ubuntu with meta-package lubuntu-desktop

They all use same repository source and software center. What can be installed in ubuntu can be easily installed in any of the three.

Basically xubuntu and lubuntu are oriented towards older hardware and low resources as they are lightweight than gnome and do not use compositing by default. Although I have not used kubuntu, its for people prefering kde to gnome. The best way to see the difference is trying it yourself. You may easily install all three DE and check it out yourself.

Xubuntu uses the default Ubuntu Software Center installed by default while Synaptic Package Manager is also available by default. Kubuntu has it's own muon software center. Lubuntu has by default no software center installed, only Synaptic. But you can install USC.
A suggestion: USB boot all three OS and try them out yourself, choose what flavour suits you best.

Yes Xubuntu is a little faster than Ubuntu although Ubuntu will use your video card to display most of the gui, all versions of Ubuntu come with mysql and python as default but if you want a truly lightweight and fast Os then try Lubuntu (uses OpenBox as gui)...

All three of these distros are basically the same thing with a different desktop environment and different default software.

Out of these three distros, my favorite is Kubuntu and my least favorite is Xubuntu. That's just my personal opinion, though. Try them all out and see which one you like the most. Try out Lubuntu, too.